LOTSY S THEORY OF EVOLUTION. 259 



effort. . . . After the blind complacency of conventional evolutionists 

 it is refreshing- to meet so frank an acknowledgment of the hardness of 

 the problem. Lotsy's utterance will at least do something to expose 

 the artificiality of systematic Zoology and Botany. 



The poor hard-working systematists might well, after these com- 

 placent words throw tip the sponge in despair, but it may be 

 just as well to examine Lotsy's theory for ourselves, and see 

 whether it can influence us in our future work. 



Lotsy starts from the assumption that evolution is possible 

 if species are constant, and that crossing is the means by which 

 it is brought about.* It appears to me, however, strange that 

 he based his theoretical views on the results of crossing Linnean 

 species of the genus AntirrJiinnui — which, if I tmderstand him 

 rightly, are heterozygotes — and consequently the very argu- 

 ments which he uses to demolish De Vries' mutation theoryf 

 can be urged against his. However, we shall let that pass. 



Lotsy defines his position in the concluding paragraph of 

 his paper| as follows : 



Briefly stated, I mean that a species, a hymozygote combination, is 

 constant ad infiiiifuiii. that it reproduces itself until its reproductive cells 

 become combined with those of another homozygote (or heterozygote), 

 and thus an exchange of " genes '' becomes possible. 



On the preceding page he says : 



I am thus of opinion that at the present time, apart, perhaps, from loss- 

 mutants, § only one kind of formation of new species has been proved, 

 namely, new combinations by crossing of " genes " which were alreadv 

 present in the parents, and that a homozygote modification, namely, a 

 pure species, is constant, apart from non-transmissible modifications 

 caused by external circumstances. 



From this follows — 



r. AH differences between the individuals of a species are non-trans- 

 missible modifications. 



2. There are (perhaps with the exception of loss-mutants) no here- 



ditary mutations or sports within a pure species. All that has 

 been described as such is the result of the splitting (vegetative 

 or generative) of heterozygote combinations. 



3. A transmission of acquired characters is impossible. 



4. All "genes" (Anlaji^en) present in higher organisms were present 



already in the totality of primitive organisms (Uror^anismen) .^ 



This does not necessarily mean that there ever was one primitive 

 organism \vith all these " genes '" ; on the contrary, it appears to me prob- 

 able that each primitive organism possessed only few " genes,'' and it is 

 just this small number of " genes " which I consider to be the cause of 

 their very limited pov.^ers of development, and I am confirmed in this view 

 by the fact that all living beings which reproduce themselves only asexually 

 have comparatively simple structure. 



* " Fortschritte unserer Auschauungen iiber Descendenz seit Darwin 

 und der jetzige Standpunkt der Frage " : J. P. Lotsy in " Progressus 

 Rei BotaniccT," 4 (1913), 37S. 



tOp. cit. 372. 



t Op. cit. 388. 



§ Caused by the loss of one genetic factor from a gamete. 



II The question how these Urorganisinoi acquire their "genes" is 

 not discussed Ijy Lotsy, and perhaps wisely so, because he would then 

 have had to show that the very difficulty which he fails to overcome as 

 regards higher organisms confronts us in the lowest, if Lotsy's views 

 are correct. 



